User:Karl E. Zahn/Sandbox RB69 1/domain-structure

DNA polymerases (pols) are a specialized class of transferase enzymes that catalyze template directed extension of a primed DNA strand from free deoxynucleoside triphosphates. The family B DNA pol encoded in the genome of the bacteriophage RB69 represents such an enzyme that shares significant homology with the human primase associated pol α, the human replicative pols δ and ε, and the human repair pol ζ. The relative ease with which one can induce RB69 pol to form diffraction quality crystals in complex with DNA, in addition to its homology shared with important human enzymes, has allowed RB69 pol to serve as an extremely useful structural tool and model enzyme.



The first crystal structure of RB69 pol, solved in 1997, revealed the domain topology characteristic of polymerases: the palm, fingers, and thumb domains obtain a spatial arrangement reminiscent of a right hand. RB69 pol also wields intrinsic 3'→5' exonuclease proofreading activity, which drastically improves the fidelity of this enzyme and occurs in most replicative pols. An N-terminal domain precedes the exonuclease domain in primary sequence, bringing the total to five domains.

Use the links below to explore the five domains of RB69 pol!


 * User:Karl E. Zahn/Sandbox RB69_1/palm-domain
 * User:Karl E. Zahn/Sandbox RB69_1/fingers-domain
 * User:Karl E. Zahn/Sandbox RB69_1/exonuclease-domain
 * User:Karl E. Zahn/Sandbox RB69_1/thumb-domain